Gas heater



oct. 1o, 1939,

` W. LINDER eAs Hausa Filed Jan. 29, 193s 2 sheets-sheet 1 f In conf/l www 7? 2 Sheets-Sheet 2 w. UNDER eAs HEATER Filed Jan. 29, 193e oct. 1o,l 1939.

@zwang ln li [In Illln rllllllllllllilllll. Il 543441. ,Inll'lflllllltritt!!!lvlllllldlllIllllllnlnllllllinllirdllvnuvllllllll llllllllllillll ya# M Patented Oct. 1G, 1939 v GAS HEATER. Willy Linder, Essen', Germany, assignor, by mesne assignments,

to Koppers Company,

Pittsburgh, Pa., a corporation of Delaware `Application January 29, 1938, Serial No. 187,752 In Germany January 30, 1937 air) heaters or hot blast stoves of the character' of the system Cowper and more particularly to such gas or air heaters which are provided 5 with a combustion shaft situated outside the cylindrical regenerator casing in which is arranged the refractory brickwork or the like serving as a heat transferring element, said combustion shaft being further provided with means for introducing the heating media (gas and air) into the regenerator and for withdrawing the heated-up media from the regenerator.

With the hot blast stoves known hitherto, both the chequerwork shaft and the combustion shaft 15 are both arranged in an essentially cylindrical single casing. When designing such a single cylindrical casing for the purpose, it is not dflicult to provide on said cylindrical casing suitable means which will permit or equalize the heat m expansion of the casing body, and the expansion due to a certain overpressure inside the heater, when being used for instance as a hot blast stove. If, however, the combustion shaft and the gas heater proper are arranged in separate g5 casings they show a different degree of heat expansion, and both the casings have to be interconnected movably, as both the casings show different heat or pressure expansions. On heating-up such a type of hot blast stove, it may 30 happen that, for instance, the casing in which is arranged the chequerwork, will expand to a higher extent'than the casing of the combustion shaft.

Now the main object of my present invention 35 is to provide such improvements in gas (or air) heaters of the character of the system Cowper, which are equipped with a combustion shaft situated outside the cylindrical casing of the regenerator gas heater proper, which improvements o will permit a suitable movement, between the casing of the combustion shaft and the casing of the gas heater, corresponding tothe above mentioned difference in heat expansion.

According to my invention, a compensating ele- 45 ment is arranged at the upper part of the combustion shaft in such a manner that the upper part or dome of the combustion shaft casing can move relatively against the lower part of the saidcombustion shaft casing, said compensating- 50 element consisting of a resilient cylindrical sheetmetal body provided with radial corrugations in such a way that the cylindrical body may be expanded or pressed-together in an axial direction. ,This compensator is, according tomy invention, connected, on the one hand, in a gastight manner withv the lower part of the combustion shaft and, on the other hand with the upper dome part of said shaft.

The arrangement of such compensating elements on the combustion shaft will permit sup- 5 porting both the casing of the gas heater proper and the casing of the combustion shaft inde` pendently on the ground. The one casing may expand or contract corresponding to its temperature relatively to the other one, without disturbing the gas-tight connection between the two casings. I

A further object of my invention is -to provide improvements in the means for supporting the upper and the lower part of the combustion shaft mentioned before.

According to the present invention, the upper part and the 4lower part of the said combustion shaft are interconnected by adjustable springs or other elastic members, bridging the said com- 20 pensating elements.

A still further feature ofmy present invention consists in that the elastic members or springs connecting the two parts of the combustion shaft are arranged in such a manner that in case the two parts o f the gas heater and the combustion shaft, respectively, tend to move relatively againsty one another, on account of a considerable change of the pressure inside the gasv heater, such a movement will be prevented whilst those changes of the compensator, which are necessary for y equalizing the dierent heat expansions' of the casing parts may still take place.

When the normal operating temperature of the casings has been arrived at, the tension of the springs connecting the upper and lower part of the combustion shaft, 'must be adjusted so that the weight of the upper part of the combustion shaft is balanced by said springs which, however.

permit a certain relative movement between the 40 two parts of the combustion shaft.

When' the gas heaters of a blast-furnace are operated in the ordinary way, the pressure inside the heater changes considerably on reversing the ow of gases in the regenerative system. During the regenerator heating-up period, 'the pressure inside the heaters is only about to 150 millimeters water gauge. When, however, the blast is heated in the regenerator gas-heater for the blast furnaces,` then a pressure of 0.7 to 1,5,at- 50 mospheres and even more is formed in the regenerator gas heater.

When the springs, which bridge the compensator and support the upper part of the combustion shaft, are .designed in such a manner that they are able to follow the movement of the casing parts according to the different heat expensions, each change of the pressure inside the gas heater will effect a certain relative movement between the two casing parts and consequently the compensator expands and contracts respec the different heat expansion between the two casing parts and will further improve the action and life of the compensator.

Other objects and features of my present invention may be taken from the following description of a mode of carrying out my invention on the lines of the accompanying drawings, of

which Figure 1 shows a vertical section through a gas heater of the system Cowper, constructed acc ording to my invention,

Figure 2 is a side View of the apparatus illustrated in Figure 3. v

Figure 3 shown on an enlarged scale is a section through. the connection between the combustion shaft dome and the combustion shaft casing, and

'I'he essentially cylindrical regenerator casing of the gas (or air) heater is marked I- on the drawings. It is built upon the foundation 2. At its upper end the casing I is connected by a slope 3 Ato the dome casing 4. The bottom of the casing has a port 5 constituting the inlet and outlet for air and gas respectively.

'I'he casing I is lined with a heat insulating material 6. As may be seen from Figure 1, the thickness of the lining decreases from the top downwards. The thick-ness of the heat protective layer 6 is adapted to the differences in temperature and heat reduction in the respective zones of the heat exchanging chequerwork, which ll-up the free space 1 inside the casing I.

The lining 8 of the heater dome 4 is supported on the inclined faces 3, independently from the brickwork 6.

From the dome 4 extends a pipe line I0- which is lined with refractory brickwork 3. said pipe leading to the dome of the combustion shaft situated by the side of the gas heater proper. The combustion shaft consists of an essentially cylindrical casing fI2 which is fitted with a refractory lining I3 and which lies near the gasheater on a suitable framing I4. Gas is introduced through the pipe line I5 from below into the combustion f shaft and air is introduced through the pipe line I6. Both pipe lines I6 and I5 enter a combustion apparatus I1, Where gas and air' are mixed with one another and from whence is developed the flame. The combustion shaft is preferably of such a height that the llame rising upwards from thel combustion apparatus I1, reactswwithin the V combustion shaft so that the sensitive chequerwork of the heater is not subjected to explosive flames. `Above the combustion apparatus IIinthe combustion shaft I2, there is also provided a branch I3 through which the medium which has been heated up in the regenerative heater 1 (for instance heated-air) is discharged.

Between the casing I2 of the combustion shaft and the dome which is preferably provided with a slope I9 for the separate supporting of the brickwork of the dome there, is placed a compensator 20 to take-up the unequal heat expansion between the casing I and the combustion shaft casing I2 together with the dome frame 4.

Details of the compensating elements may be taken from Figures 2 and 3. The compensator 20 connects the flange 2I,adjoining the slope I9 of-the dome casing II, with the casing I2. It consists, for instance, of a pipe piece which is corrugated once or several times, having a bulge lying outside. The cavities of the compensator 20 are sealed at the inside by a sheet-plate wall 22 which is designed movably.

In the apparatus shown on the drawings, the dome casing I I is rigidly connected with th heater casing I so that the weight of the combustion shaft dome I I is also carried by the heater casing I. At the slope I9 of the combustion shaft casing, are several brackets 23 into which engage the tide-rods 5, which can be disconnected, and which are provided with a head 24. These tierods 25 extend through a suitable recess in each bracket 21 provided therefor at the upper end of the combustion shaft casing. Setting nuts 29, holding a pressure plate 30 are bolted on the threaded end 28 of the tie-rods 25. The pressure plates 3| are connected with the pressure plates 30 by means of adjustable tie-rods 32. Springs 33 are inserted between the plates 30, 3|. By means of the tie-rods 32, the springs 33are held 'pressed together in such-a. manner that they have a certain initial tension. During the heating-up of the gas heater, the set nuts 29 of the tie-rods 25 are adjusted in such a way that the upper pressure plate 3| for the springs 33 is always placed at a certain distance from the pressure face of the brackets 21. Assoon as the operating temperature has been obtained, the nuts 25 are adjusted so that a small space a is left between the brackets 21 and the pressure plates 3|. The

space "a is so large that it corresponds to the latter being rigidly connected with it, so that the pressure plates 3| t tightly againstgthe brackets 21. Each further longitudinal expansion of the combustion shaft which might lead to a one-sided load of the casing I, is then taken-up by the springs 33 in such a manner that the combustionI shaft dome practically remains in its position or only small and harmless movements will take place.

Preferably, the pressure plates 3| of the tierods 25 are s o adjusted that the pressure plates 3| will engage against the corresponding brackets 21, one after the other. The initial tension of the springs 33 is so chosen that one of the springs 33 `alone cannot offer the necessary resistance against the upwardsI movement of the combustion shaft dome caused by the pressure inside the heater, but only all of the springs 33.

Consequently, those springs 33 of the pressure plates 3| which engage against the brackets 21 CIV before the others,' are pressed together to a small extent until finally all the springs 33 are stressed. At this moment, the combustion shaft dome is practically maintained inits exact position and any further movement which might lead toa warping of the heater dome, is eliminated.

I'he insertion of the springs 33 offers the advantage in that at in increased pressure,'the combustion shaft dome isable to follow exactly the considerable movement of the gas heater. In those instances where a constant over-pressure exists during the operating period,it is also possible to eliminate the springs and to replace them by rigid adjustable stops..

Instead of supporting the combustion shaft dome Il rigidly upon the casing |2, it may also be of advantage under certain conditions to support the weight of the combustion shaft dome il, together with the necessary brickwork and the connecting line, elastically on the casing I2 of the combustion shaft. For this reason, adjustable pressure springs like the springs 33 may also be inserted between the brackets 23 and 21, as diagrammatically indicated at 33 in Fig. 3. These springs will have such an initial tension that, under normal conditions, they carry the weight of the combustion shaft 'dome With the connecting line. The combustion shaft dome is able to follow in such a case every expansion of the gas heater dome, in which event the tie-rods 25 together with th'e adjustable stops will have been arranged in such a manner that the upward movement ofthe combustion shaft dome is in no event higher than that of the gas heater dome. In this way, any distortion of the con` nection line between the gas heater dome and the combustion shaft dome is eliminated, thus preventing the casing from any leakage which may otherwise take place at this point.

I have now described the present invention on the lines of a preferred embodiment thereof, but myinvention is not limited in all its aspects to the mode of carrying it out as described and shown, since the invention may be variously embodied within the scope of the following claims.

I claim:

1. In a regenerative heater comprising a regenerator constituted of a tower-like metal casing inner-lined with refractory brickwork and haying regenerator checkerbrick inside the same; .a'tombustion shaft therefor arranged outside the same and constituted of a tower-like metalcasinginner-lined with refractory brickwork; and a conduit connecting the top of the regenerator with the top of the combustion shaft said co'nduit comprising a metal-encased refractory dome supported by the regenerator and a metal-encased refractory dome supported by fthe cornbustion shaft; the combination of compensator means for accommodating the difference in expansion between the regenerator and its dome and the combustion shaft and its dome, of pressure-resisting means for limiting the .movement of the conduit under increased internal gas pressure, and of flexible meansfor supporting the conduit, said compensator comprising an expansion joint interposed between and adapted to connect the casing of the combustion shaft dome with the casing of the combustion shaft proper in gas tight relation while permitting expansive movement of the same axially of the combustion shaft proper, said pressure resisting means comprising adjustable means bridging the compensator and connecting the combustion shaft dome casing with the casing of the combustion shaft proper to limit the movement of the combustion shaft dome under internal gas pressure, and said flexible supporting means comprising adjustableV spring means interposed between the combustion-shaft dome-casing and the casing of the combustion shaft proper to cushion the weight of the dome on the shaft.

2. In a regenerative heater comprising a regenerator constituted of a tower-like metal casing inner-lined with lrefractory brickwork and having regenerator checkerbrick inside the same; a combustion shaft therefor arranged outside the same and constituted of a tower-like metalcasing inner-lined with refractory brickwork; and a conduit connecting the top of the regenerator with the top of the combustion shaft said conduit comprising a metal-encased refractory dome supported by the regenerator and a metalencased refractory dome supported by the combustion shaft; the combination of compensator means for accommodating the difference in expansion between' the regenerator and its dome and the combustion shaft and its dome, of pressure-resisting means for limiting the movement of the conduit under increased internal gas pressure, said compensator comprising an expansion joint interposed between'and adapted to connect the casing of the combustion shaft dome with the casing of the combustion shaft proper in gas tight relation while permitting expansive movement of the same axially of the combustion shaft proper', said pressure resisting means comprising adjustable means bridging the compensator and connecting the combustion shaft dome cas- -ing with the casing of the combustion shaft *proper to limit the movement of the' combustion shaft dome under internal gas pressure.

3. In a regenerative heater comprising a regeneratorconstituted of la tower-like metal casing inner-lined with refractory brickwork and having regenerator checkerbrick inside the same;

a combustion shaft therefor arranged outside the same and constituted of a'tower-like metal-casing inner-lined-with refractory` brickwork; and a conduit connecting the top of the regenerator with the top of the combustion shaf-t said conduit comprising a metal-encased refractory dome supported by. the regenerator andwa metal-encased refractorydome supported by the combustion shaft; the combination of pressure-resisting means for limiting the movement of the conduit under increased internal gas pressure, said pressure resisting means comprising adjustable means connecting the combustin, shaft dome casing with the casing of the combustion shaft proper to limit the movement of the combustion shaft dome under internal gas pressure.

4. In a regenerative heater comprising a re-v y generator constituted of a tower-like metal cas? ing inner-lined wi-th refractory brickworl; and having regenerator checkerbrick inside the same;

a combustion shaft 'therefor arranged outside.

the same and constituted of a tower-like metalcasing inner-lined with refractory brickwork; and a conduit connecting the top of the regenerator with the top of the combustion shaft said compensator comprisingan expansion joint interposed between and adapted tol connect the casing of the combustion shaft dome with the 'casing of the combustion shaft proper in gas tight relation while permitting expansive movement of the same axially of the combustion shaft proper.

5. In a regenerative heater comprising a regenerator constituted of a tower-like metal casing inner-lined with refractory brickwork and having regenerator checkerbrick inside the same; a combustion .shaft therefor arranged outside the same and constituted of a tower-like metalcasing inner-lined with refractory brickwork; and a conduit connecting the top of the regerierator with the top of the combustion shaft. said conduit comprising a metal-encased refractory dome supported by the regenerator and a metalencased `refractory dome supported by the combustion shaft; the combination of flexible means for supporting the conduit, and said flexible supporting means comprising adjustable spring means interposed between the combustion-shaft 5 

